1. Field of the Invention
The present invention relates to clearance retaining devices that may assure an optimal clearance between a movable jaw of an adjustable wrench and an article held between the movable jaw and the fixed jaw.
2. Description of the Related Art
FIG. 9 illustrates a typical adjustable wrench that has a fixed jaw 12' and a movable jaw 13'. When driving a nut (not shown), the adjusting screw 14' is rotated until the space between the jaws 12' and 13' is capable of receiving the nut. Next, the movable jaw 13' is moved toward the fixed jaw 12' to tightly clamp the nut. Typically, an end wall of the movable jaw 13' generally has an angle .alpha. (about 0.5.degree.) to a plane that is parallel to an inner wall of the fixed jaw 12'. Nevertheless, in order to allow easy disengagement of the adjustable wrench and the nut, the user generally has to proceed with minor adjustment by means of rotating the adjusting screw 14' again to move the movable jaw 13' slightly away from the fixed jaw 12' to thereby obtain an optimal clearance. However, such minor adjustment is difficult to achieve. The faces or edges of the nut will be damaged if the minor adjustment goes too far. To the contrary, it is difficult to disengage the adjustable wrench from the nut if the minor adjustment is not enough. In addition, the movable jaw 13' and the adjusting screw 14', even if the minor adjustment is achieved, will be moved upon repeated operation of the adjustable wrench on the nut. Furthermore, the adjusting screw 14' might be inadvertently impinged by the user's fingers or any articles and thus causes a change in the clearance. As a result, there is a high risk of damage to the nut. Use of adjustable wrenches is even prohibited in certain cases.
It is therefore a long and unfulfilled need in the adjustable wrench with a clearance retaining device to reliably retain the adjustable wrench in an optimal clearance.